How Polar Bears Survive on 'Heart Attack' Diet

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If humans ate the same fatty foods as polar bears, they would
have heart attacks. But a new study reveals how these magnificent
Arctic beasts survive on such a specialized diet.

It turns out the beasts have evolved genes that allow them to
survive on a diet of mostly seals and the blubber those animals
contain, not to mention their sky-high cholesterol levels,
without developing
heart disease.

"In this limited amount of time, polar bears became uniquely
adapted to the extremities of life out on the Arctic sea ice,
enabling them to inhabit some of the world's harshest climates
and most inhospitable conditions," study leader Rasmus Nielsen, a
theoretical evolutionary biologist at the University of
California, Berkeley, said in a statement.

In their study, Nielsen and his colleagues sequenced the complete
genomes of 79 polar bears from Greenland and 10 brown bears from
around the world. The researchers discovered that polar
bears and brown bears branched off from a common ancestor
sometime in the last 500,000 years, compared with previous data
that suggested the two species diverged up to 5 million years
ago.

Since splitting off from brown bears, polar bears have evolved
quickly through mutations in genes that play roles in heart
function and the metabolism of fatty acids, the study found.
These same genes have been linked to human heart disease

The dramatic genetic changes in response to a fatty diet have not
been reported before, suggesting that scientists should look
beyond standard model organisms in studying the genetic causes of
human heart disease, the researchers said.